Commercial vehicles with a large number of gear ratios frequently exhibit a speed range gear which is connected to the principal gear with its gear ratios. By means of a speed range gear, the overall multiplication factor of the principal gear can be increased, because all of the gear ratios of the principal gear can be used together with each gear ratio of the speed range gear, and in at least one gear ratio of the speed range gear, the multiplication factor of the gear ratios of the principal gear can be reduced and/or increased.
A speed range gear for automobiles has been disclosed, by way of example, in DE 41 21 709 A1. A planetary gear of this type, installed downstream of the principal gear, provides the possibility of operating the automobile in two different speed ranges for each of the gear ratios of its principal gear. In a first slowed-down gear ratio level of the speed range gear, the annulus of the planetary gear is coupled to the gearbox by means of a switching clutch, so that the output shaft of the speed range gear exhibits a lower revolution speed than the output shaft of the principal gear. In a second gear ratio level, direct transmission takes place from the output shaft of the principal gear to the output shaft of the speed range gear, whereby the direct connection between the output shaft of the principal gear and the output shaft of the speed range [gear] is created by means of a switching clutch. The switching device is extremely complex.
DE 198 51 895 A1 describes an additional speed range gear in the form of a planetary gear. In that publication, the annulus of the planetary gear is connected in a torque-proof manner to the gearbox. The sun gear of the planetary gear is arranged coaxially to the output shaft of the main gear and is freely rotatable relative to the output shaft of the principal gear. In order to create a reduction ratio between the output shaft of the principal gear at the output shaft of the speed range gear, the sun gear can be connected in a torque-proof manner to the output shaft of the principal gear. This planetary gear is also complex and problematic for the mounting of individual components.
The invention is based on the task of improving a planetary gear and especially the component mounting.